diff --git a/appinfo/info.xml b/appinfo/info.xml
index 4687a8f..bdbfb31 100644
--- a/appinfo/info.xml
+++ b/appinfo/info.xml
@@ -8,7 +8,7 @@ Search for torrents within the app from mutiple BT sites;
 Control Aria2 and manage download tasks from the web;
 download videos from 700+ video sites(youtube,youku,vimo,dailymotion,twitter,facebook and the likes
 </description>
-    <version>0.8.0</version>
+    <version>0.9.0</version>
     <licence>agpl</licence>
     <author mail="freefallbenson@gmail.com" homepage="https://github.com/shiningw">jiaxinhuang</author>
     <namespace>NCDownloader</namespace>
diff --git a/lib/Command/Aria2Command.php b/lib/Command/Aria2Command.php
index 4df71ff..d19e785 100644
--- a/lib/Command/Aria2Command.php
+++ b/lib/Command/Aria2Command.php
@@ -9,7 +9,7 @@ use Symfony\Component\Console\Input\InputArgument;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Output\OutputInterface;
 
-class Aria2Command extends base
+class Aria2Command extends Base
 {
     public function __construct()
     {
diff --git a/lib/Controller/Aria2Controller.php b/lib/Controller/Aria2Controller.php
index b4a5b88..1951872 100644
--- a/lib/Controller/Aria2Controller.php
+++ b/lib/Controller/Aria2Controller.php
@@ -186,7 +186,7 @@ class Aria2Controller extends Controller
             if ($row = $this->dbconn->getByGid($gid)) {
                 $filename = $row['filename'];
                 $timestamp = $row['timestamp'];
-                $extra = unserialize($row['data']);
+                $extra = $this->dbconn->getExtra(($row['data']));
             } else if (isset($value['files'][0]['path'])) {
                 $parts = explode("/", ($path = $value['files'][0]['path']));
                 if (count($parts) > 1) {
diff --git a/lib/Controller/MainController.php b/lib/Controller/MainController.php
index fbaacb6..572447d 100644
--- a/lib/Controller/MainController.php
+++ b/lib/Controller/MainController.php
@@ -32,7 +32,6 @@ class MainController extends Controller
         $this->uid = $UserId;
         $this->l10n = $IL10N;
         //$this->rootFolder = $rootFolder;
-        OC_Util::setupFS();
         $this->aria2 = $aria2;
         $this->aria2->init();
         $this->urlGenerator = \OC::$server->getURLGenerator();
diff --git a/lib/Tools/YoutubeHelper.php b/lib/Tools/YoutubeHelper.php
index b8d66da..4e9cc8d 100644
--- a/lib/Tools/YoutubeHelper.php
+++ b/lib/Tools/YoutubeHelper.php
@@ -17,6 +17,7 @@ class YoutubeHelper
     public $file = null;
     public $filesize = null;
     protected $pid = 0;
+    private static $instance = null;
     public function __construct()
     {
         $this->dbconn = new DbHelper();
@@ -26,7 +27,12 @@ class YoutubeHelper
 
     public static function create()
     {
-        return new static();
+
+        if (!self::$instance) {
+            self::$instance = new static();
+        }
+
+        return self::$instance;
     }
     public function getFilePath($output)
     {
diff --git a/src/components/mainForm.vue b/src/components/mainForm.vue
index 0e205df..bfd6a98 100644
--- a/src/components/mainForm.vue
+++ b/src/components/mainForm.vue
@@ -26,45 +26,15 @@
         <div class="download-controls-container">
           <div v-if="checkboxes" id="select-value-extension-container">
             <select :value="selectedExt" id="select-value-extension">
-              <option
-                id="defaultext"
-                :value="defaultext"
-              >
-                Default
-              </option>
+              <option id="defaultext" :value="selectedExt">Default</option>
               <optgroup label="Video">
-                <option
-                  id="mp4"
-                  value="mp4"
-                >
-                  mp4
-                </option>
-                <option
-                  id="webm"
-                  value="webm"
-                >
-                  webm
-                </option>
+                <option id="mp4" value="mp4">mp4</option>
+                <option id="webm" value="webm">webm</option>
               </optgroup>
               <optgroup label="Audio">
-                <option
-                  id="m4a"
-                  value="m4a"
-                >
-                  m4a
-                </option>
-                <option
-                  id="mp3"
-                  value="mp3"
-                >
-                  mp3
-                </option>
-                <option
-                  id="vorbis"
-                  value="vorbis"
-                >
-                  vorbis
-                </option>
+                <option id="m4a" value="m4a">m4a</option>
+                <option id="mp3" value="mp3">mp3</option>
+                <option id="vorbis" value="vorbis">vorbis</option>
               </optgroup>
             </select>
           </div>